This invention relates to reading and recording magnetic data, and more particularly to apparatus for supporting a magnetic transducing head with respect to a rigid carriage in a manner that permits the head to respond to slight surface irregularities in a substantially planar magnetic recording surface.
It is known in the art to support magnetic transducing heads to facilitate gimbaling action, i.e. tilting about axes parallel to a magnetic recording surface and perpendicular to each other, and moving linearly or along an arc parallel to the recording surface plane. For example, U.S. Pat. No. 4,328,521 (Pexton) discloses a gimbal spring with a pair of opposing legs, a ring, and a platform within the ring. Transverse bands between the arms and outer ring, and longitudinal bands between the outer ring and gimbal platform, cooperate to allow tilting, with the legs sufficiently flexible to permit the required linear movement. A load arm biases the head toward the recording surface. This or other gimbal springs are employed with heads that contact the recording surface, or with heads that "fly" parallel to and spaced apart from the recording surface, supported by a bearing or cushion of air. The freedom for gimbaling movements is particularly important in connection with flying heads, as it allows head positioning close to the recording surface while minimizing the chance for a head crash, i.e. an unintended, often damaging contact of the head and recording surface.
Transducing head suspensions have competing needs. First, a suspension should be flexible, to permit rapid response to recording surface irregularities. However, for more accurate head positioning and improved dynamic performance, the resonant frequency of the support system should be high, and this calls for high stiffness. Typically, these competing needs are balanced by providing three separate components in a head suspension system: a highly flexible gimbal component; somewhat less flexible support arms; and a comparatively rigid but still elastic load spring.
Further examples of suspension systems include one in U.S. Pat. No. 4,286,297 (Root) having two relatively rigid tapered legs, with flexible sections at opposite ends of the legs. Consequently, when the slider is loaded near the recording surface, both flexible ends bend, at least in theory, to maintain the slider parallel to the disc surface. A boss directly aligned with the head is loaded through a movable lid 40. U.S. Pat. No. 3,931,641 (Watrous) shows a flexure for mounting an air bearing slider including relatively thin flexible longitudinal fingers joined by cross-legs which are stiffer than the fingers due to their greater width. A loading force is applied by a load beam, acting on a protuberance 40 above the head.
U.S. Pat. No. 3,864,748 (Herdman) shows an attitude spring and a load spring, both flat, horizontally disposed and spaced apart from one another. A flexible cross-member joins opposed longitudinal arms of the attitude spring. While each of the above examples is satisfactory to a degree, all are complex and difficult to control accurately in production, and necessarily involve a compromise between the desired high resonant frequency and rapid gimbaling response.
Therefore, it is an object of the present invention to provide a simplified, and more reliable and consistent magnetic head suspension.
Another object of the invention is to achieve improved dynamic performance by reducing off-track motions of a transducer core, and by minimizing fluctuations in flying height.
Another object is to employ the air bearing of a flying head in connection with the head suspension, to substantially increase the resonant frequency of the suspension.
Another object of the invention is to provide a head suspension system in which a single flat component provides positioning of the head and also provides gimbaling action, without bends or curves formed into it.
Yet another object of the invention is to provide a preformed load spring designed to be nominally flat during operation, thereby minimizing its vibration.